My sentiment too It's a piece of work from a lab, some prototype, a possible basis for a bioweapon they probably suspected would eventually be used against them at one point so they worked on that to figure possible counter measures, and shit happened, stuff got out. How? Who really cares, it's there now Lethality isn't that high, while it could have been much higher in the case of a true bioweapon, so yeah, that's mostly why I believe you're right. Also, vast majority of coronaviruses known since the 60s are rather harmless, and this one is a champ for some odd reason... So yeah that's when the engineered part seems likely, it's not just randomness imo